The semiconductor integrated circuit (IC) industry has experienced rapid growth. In the course of the IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. Such scaling down has also increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC manufacturing are needed.
For example, as the semiconductor industry has progressed into nanometer technology process nodes in pursuit of higher device density, higher performance, and lower costs, challenges from both fabrication and design have resulted in the development of devices having doped regions. An ion implantation process is well suited for doping. Ion implantation adds dopant atoms in a material using energetic ion beam injection. It is important to achieve uniform implantation. If the implantation is not uniform, the dopant profile and ultimately the electronic device may be adversely affected. One reason why implantation may not be uniform is because the angle of incidence if the ion beam varies. For example, the incidence angle of an ion beam may vary because of beam blow-up. Beam blow-up occurs because as the ion beam travels from the source chamber the positive ions within the ion beam to mutually repel each other. Such mutual repulsion causes a beam of otherwise desired shape to diverge away from an intended beamline path. Consequently, it is desirable to monitor the incidence angle of the ion beam in an ion implanter so that control of the ion implantation process may be improved. Although existing devices and methods of monitoring ion beam incidence angle have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects.